> “As a result of the changes in systems, flights under different numbering systems could have the same number with one having a letter appended, e.g. flight STS-51 (a mission carried out by Discovery in 1993) was many years after STS-51-A (Discovery's second flight in 1984).[6] It wasn't until STS-127 in 2009 where the flight numbering system returned to a standard and consistent order.”

Ouch, shortly after they get standardized and consistent flight numbers, the shuttle program gets cancelled. I guess computer science doesn’t have a monopoly over the difficulty of naming things.